1. Field of the Invention
This invention relates to the drying of water-wet porous materials.
2. Description of the Prior Art
Conventional methods of drying water-wet porous materials by evaporation of the water consume large amounts of energy because of the high specific heat and latent heat of vaporization of water. Water-wet nonporous or nonabsorbent materials may be dried, at a lower energy investment, by displacing the water from the surfaces of the materials by means of water-immiscible organic displacement liquids. U.S. Pat. No. 3,397,150 discloses such a process for displacing water from nonabsorbent surfaces by means of spraying or dipping techniques. The displacement liquid consists of a 1,1,2-trichloro-1,2,2-trifluoroethane solution of an alkyl phosphate neutralized with an alkylamine. U.S. Pat. No. 3,386,181 discloses a continuous process for displacing water from nonabsorbent surfaces using, for example, the dislacement liquids of U.S. Pat. No. 3,397,150. Belgian Pat. No. 810,949 discloses a water displacement liquid composition comprising (a) a fluorine-containing compound having a solubility parameter of less than about 8, a density of at least about 1.3g./cc. at room temperature and a boiling point above about 20.degree.C. and (b) a surfactant dissolved in (a) to the extent of about 0.01-5% by weight of the composition, the composition characterized by an interfacial tension with water of up to about 6 dynes/cm. and a water solubilization index of less than about 750 ppm. U.S. Pat. No. 3,003,247 discloses a process for displacing water from nonabsorbent surfaces of articles such as glass wool, woven glass fabrics and nylon and polyester filaments by means of displacement liquids consisting of chlorinated hydrocarbon solutions of cationic surface-active agents.